Brega

Brega was an Irish petty kingdom which existed from the 425 to 1170 AD. It was founded by descendants of the O'Neill clan, and its kingdom included the Hill of Tara. During the 6th century, it was conquered by Ailech, and it split into two hostile branches during the 8th century. Brega was threatened by the Viking kingdom of Dyflin during the Viking invasions of Ireland and came under the suzerainty of Mide, and it was conquered by England during the Norman invasion of Ireland in 1170.